Augmented reality, or AR, is a rapidly developing area of interaction design. The point of AR is to enhance your surroundings, whether you're visiting a new city, reading a book, or shopping for groceries. It's similar to the idea of virtual reality, but instead of sweeping you out of your environment into an alternate world, AR enhances what's already around you. At the moment, ideas in AR are outpacing technology. The Internet is abuzz with simulation videos, unrealized prototypes, and early-stage designs that lean on existing technologies. The designs incorporate smartphones, projection mapping, and 3-D motion-capture devices as building blocks. One exciting AR application is Berlin Wall 3-D, created with Layar, an open AR platform for smartphones.

Berlin Wall 3-D allows viewers to see exactly where the Berlin Wall once stood.

If you raise your smartphone to the former site of the Berlin Wall, the app superimposes a 3-D rendering of the wall onto the real scene in front of you. Created by German developers Hoppala and Superimpose, the app uses the built-in camera, accelerometer, magnetometer, and gyroscope of any smartphone to blend imagery from the past and present in real time.

Monday Enhancements is a weekly series on interaction design and augmented reality.